Such a mat is, for example, known from EP 1 157 241 B1. The carrying sheet has the form of a grid, on which a heating cable is arranged in a snake shape, longitudinal sections of the heating cable extending in parallel with grid wires. The heating cable is fixed on the top side of the carrying sheet by means of a grid-shaped adhesive tape. An adhesive material is put onto the bottom side of the grid. This adhesive material serves the purpose of fixing the grid on a foundation when installing the mat. When the mat has been fixed onto the foundation, for example a plaster or the like, it is covered by another layer, for example a filler or a tile cement.
In the most cases, this method will be sufficient for fixing the heat conducting mat on the floor.
In connection with certain substances, which are put onto the heat conducting mat, particularly self-levelling pouring compounds with a high water content, however, this kind of fixing may cause problems. The water can namely be able to penetrate under the adhesive material, so that the heat conducting mat disengages from the underground and lifts or swims up to the surface of the pouring compound. This does not only require an additional refinishing, which can involve substantial efforts and costs. Also the temperature profile of the floor, in which the heat conducting mat is located, will then be unequal, that is, areas exist, in which the layer covering the heat conducting mat is thinner than in other areas, so that here a higher temperature is obtained on the surface of the floor.